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31
Impact of Imperfect Channel Estimation on the Performance of Amplify-and-Forward Relaying
"... Abstract—In this paper, we investigate the error rate performance of amplify-and-forward (AF) relaying with imperfect channel estimation. We consider a single-relay scenario with orthogonal and non-orthogonal AF (OAF and NAF) cooperative protocols. Two pilot-symbol-assisted receiver architectures ar ..."
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Cited by 23 (1 self)
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Abstract—In this paper, we investigate the error rate performance of amplify-and-forward (AF) relaying with imperfect channel estimation. We consider a single-relay scenario with orthogonal and non-orthogonal AF (OAF and NAF) cooperative protocols. Two pilot-symbol-assisted receiver architectures are studied: In the mismatched-coherent receiver, the complex fading channel coefficients (i.e., both phase and amplitude) are estimated based on a linear minimum-mean-squared-error estimation approach and fed to a coherent sub-optimal maximum likelihood decoder as if the channels were perfectly known. In the partiallycoherent receiver, channel amplitude is ignored and phase is estimated by a phase locked loop. For both receiver types, we analyze the achievable diversity orders for cooperative protocols under consideration and quantify the impact of channel estimation through the derivation of pairwise error probability. Our performance analysis reveals that a second order diversity order is obtained for the considered single-relay scenario indicating that full diversity is extracted. Our simulation results demonstrate that the performance degradation due to channel estimation with respect to the genie bound (i.e., perfect channel state information) is as small as 1.1dB based on the employed detector. Performance results further show that partially-coherent receiver presents a similar performance to mismatched-receiver for sufficiently large loop SNRs although channel amplitude is completely ignored. Index Terms—Transmission technology, cooperative diversity, space-time coding.
Coherent Versus Non-Coherent Decode-and-Forward Relaying Aided Cooperative Space-Time Shift Keying
"... Abstract—Motivated by the recent concept of Space-Time Shift Keying (STSK), we propose a novel cooperative STSK family, which is capable of achieving a flexible rate-diversity tradeoff, in the context of cooperative space-time transmissions. More specifically, we first propose a Coherent cooperative ..."
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Cited by 9 (5 self)
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Abstract—Motivated by the recent concept of Space-Time Shift Keying (STSK), we propose a novel cooperative STSK family, which is capable of achieving a flexible rate-diversity tradeoff, in the context of cooperative space-time transmissions. More specifically, we first propose a Coherent cooperative STSK (CSTSK) scheme, where each Relay Node (RN) activates Decodeand-Forward (DF) transmissions, depending on the success or failure of Cyclic Redundancy Checking (CRC). We invoke a bitto-STSK mapping rule, where according to the input bits, one of the
Cooperative communications over flat fading channels with carrier offsets: A doubledifferential modulation approach
- EURASIP J. Adv. in Signal Process
, 2008
"... In this paper, we propose double-differential (DD) modulation for the amplify-and-forward protocol over Nakagami-m fading channels with carrier offsets. We propose an emulated maximum ratio combining (EMRC) decoder, which could be used by the double-differential receiver in the absence of exact chan ..."
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Cited by 3 (1 self)
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In this paper, we propose double-differential (DD) modulation for the amplify-and-forward protocol over Nakagami-m fading channels with carrier offsets. We propose an emulated maximum ratio combining (EMRC) decoder, which could be used by the double-differential receiver in the absence of exact channel knowledge. Approximate bit error rate (BER) analysis is performed for the proposed double-differential modulation based cooperative communication system. The proposed double-differential system is immune to random carrier offsets, whereas the conventional single-differential modulation based cooperative system breaks down. In addition, the proposed scheme is able to perform better than the same rate training based cooperative system which utilizes training data for finding estimates of carrier offsets and channel gains. I.
The resource-optimized differentially modulated hybrid AF/DF cooperative cellular uplink using multiple-symbol differential sphere detection
- IEEE Signal Processing Letters
, 2009
"... Abstract—In multiuser cellular uplinks, cooperating mobiles may share their antennas in order to achieve transmit diversity by formig a virtual antenna array (VAA) in a distributed fashion. In this paper, based on the minimum BER criterion, we investigate cooperating-user-selection (CUS) and adaptiv ..."
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Cited by 2 (1 self)
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Abstract—In multiuser cellular uplinks, cooperating mobiles may share their antennas in order to achieve transmit diversity by formig a virtual antenna array (VAA) in a distributed fashion. In this paper, based on the minimum BER criterion, we investigate cooperating-user-selection (CUS) and adaptive-power-allocation (APA) for two types of differentially modulated cooperative cellular uplinks requiring no channel state information (CSI) at the receiver, namely, for the differential-amplify-and-forward (DAF) and the selective differential-decode-and-forward (DDF) assisted systems. They both employ multiple-symbol differential sphere detection (MSDSD) to combat rapid-fading-induced performance degradation. More specifically, we investigate the cooperative-protocol-selection (CPS) of the uplink system in conjunction with a beneficial CUS as well as the APA scheme in order to further improve the achievable end-to-end performance, leading to a resource-optimized hybrid AF/DF cooperative system. Index Terms—Cooperative cellular uplink, cooperative resource optimization, , hybrid cooperative protocol, multiple-symbol differential sphere detection. I.
Differential Amplify-and-Forward relaying in timevarying Rayleigh fading channels
- in 2013 IEEE Wireless Communications and Networking Conference (WCNC
, 2013
"... ar ..."
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Differential Modulation for Multi-Node Amplify-and-Forward Wireless Relay Networks †
"... Abstract — In this paper, we propose a multi-node differential amplify-and-forward scheme for cooperative communications. The proposed scheme efficiently combines signals from the direct and multiple relay links to improve communication reliability. Bit-errorrate (BER) analysis for M-ary differentia ..."
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Cited by 2 (1 self)
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Abstract — In this paper, we propose a multi-node differential amplify-and-forward scheme for cooperative communications. The proposed scheme efficiently combines signals from the direct and multiple relay links to improve communication reliability. Bit-errorrate (BER) analysis for M-ary differential phase shift keying is provided as performance measure of the proposed scheme, and optimum power allocation is investigated. While the exact BER formulation of the proposed scheme is not available currently, we provide as a performance benchmark a tight BER formulation based on optimum combining weights. A simple BER upper bound and a tight BER approximation show that the proposed scheme can achieve the full diversity which equals to the number of cooperating nodes. We further provide simple BER approximation in order to provide analytical result on power allocation scheme. A closed-form optimum power allocation based on the tight simple BER approximation is obtained for single-relay scenario. An approximate optimum power allocation scheme is provided for multi-relay systems. The provided BER formulations are shown to closely match to the simulation results. Moreover, simulation results show that the optimum power allocation scheme achieves up to 2 dB performance gain over the equal power allocation scheme. I.
Distributed Double-Differential Orthogonal Space-Time Coding for Cooperative Networks
"... Abstract — In this paper, distributed double-differential coding is proposed to avoid the problem of carrier offsets in amplify and forward protocol based cooperative network with two relays. A double-differential orthogonal-space-time block code is trans-mitted by the relays in a distributed manner ..."
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Abstract — In this paper, distributed double-differential coding is proposed to avoid the problem of carrier offsets in amplify and forward protocol based cooperative network with two relays. A double-differential orthogonal-space-time block code is trans-mitted by the relays in a distributed manner without channel knowledge. We derive a low complexity linear decoder which does not require the channel and carrier offset knowledge. A pairwise error probability (PEP) analysis is also conducted and we found an upper bound of the PEP for the proposed system. In addition, an optimized power allocation is proposed to improve the SER performance of the system. I.
Amplify-and-forward relaying with M-FSK modulation and coherent detection
- IEEE Trans. On Communications
"... Abstract—This paper develops a detection scheme based on the implicit pilot-symbol-assisted architecture of M-ary frequency-shift-keying (FSK) modulation in amplify-and-forward (AF) multiple-relay networks. It is shown that, at the expense of the low spectral efficiency inherent in FSK modulation, e ..."
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Cited by 1 (0 self)
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Abstract—This paper develops a detection scheme based on the implicit pilot-symbol-assisted architecture of M-ary frequency-shift-keying (FSK) modulation in amplify-and-forward (AF) multiple-relay networks. It is shown that, at the expense of the low spectral efficiency inherent in FSK modulation, every transmitted symbol from the source to the destination can be used as a pilot symbol. In the proposed detection scheme, the destination combines the signals from the source and the relays to perform detection by using the estimated channels obtained from the implicit pilot symbols. Using the Gaussian approximation for the effective noise at the destination, an upper bound of the approximated bit-error-rate (BER) is provided. Simulation results reveal that the proposed scheme can significantly improve the BER performance when compared to previously proposed schemes in a temporally-correlated fading environment. The simulation results also verify the obtained upper bound on the approximated BER. Index Terms—Cooperative diversity, relay communications, frequency-shift-keying, fading channel, amplify-and-forward protocol. I.
Distributed Linear Convolutional Space-Time Coding for Two-Relay Full-Duplex Asynchronous Cooperative Networks
"... Abstract—In this paper, a two-relay full-duplex asynchronous cooperative network with the amplify-and-forward (AF) protocol is considered. We propose two distributed space-time coding schemes for the cases with and without cross-talks, respectively. In the first case, each relay can receive the sign ..."
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Cited by 1 (0 self)
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Abstract—In this paper, a two-relay full-duplex asynchronous cooperative network with the amplify-and-forward (AF) protocol is considered. We propose two distributed space-time coding schemes for the cases with and without cross-talks, respectively. In the first case, each relay can receive the signal sent by the other through the cross-talk link. We first study the feasibility of cross-talk cancellation in this network and show that the cross-talk interference cannot be removed well. For this reason, we design space-time codes by utilizing the cross-talk signals instead of removing them. In the other case, the self-coding is realized individually through the loop channel at each relay node and the signals from the two relay nodes form a space-time code. The achievable cooperative diversity of both cases is investigated and the conditions to achieve full cooperative diversity are presented. Simulation results verify the theoretical analysis. Index Terms—Distributed space-time code, full-duplex, coop-erative communications, asynchronous cooperative diversity. I.
Performance Analysis of Modied STBC Scheme for Cooperative MIMO Communications
"... The cooperative MIMO communications is a new challenge to provide more reliable transmissions from the collaboration between users. Mostly, the MIMO employment is performed by using a simple diversity scheme. However, there are many MIMO schemes that can be implemented in practice. This paper propos ..."
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The cooperative MIMO communications is a new challenge to provide more reliable transmissions from the collaboration between users. Mostly, the MIMO employment is performed by using a simple diversity scheme. However, there are many MIMO schemes that can be implemented in practice. This paper proposes the modied STBC scheme for cooperative MIMO communications. Also the performance anal-ysis of the proposed system in term of the data er-ror rate and the outage probability is originally pre-sented. The simulation results indicate that the pro-posed system can oer a better bit error rate and improve the outage probability than the diversity scheme.
